The study aimed to evaluate the efficiency of essential oil concentrations on Cinnamomum zeylanicum leaves as a possible fungicide against mycelial growth, and the sporulation of Corynespora cassiicola in papaya seedling and fruit. The study performed three experiments, namely comparison of the anti-C. cassiicola activity of: 1 µL mL-1 C. zeylanicum essential oil, commercial fungicide, and controltreatment; comparison of the anti-C. cassiicola activity of five essential oil concentrations (0.0, 0.5, 1.0, 2.0, and 4.0 µL mL-1) and a commercial fungicide (150 g ha-1 i.a.); and the effect of applying essential oil concentrations (0.0, 0.5, 1.0, 2.0 and 4.0 µL mL-1) before and after the application of mycelium disk fungus. It was found that the essential oil from C. zeylanicum inhibits mycelial growth and sporulation of the C. cassiicola fungus. The essential oil was able to maintain lower percentage of leaves with lesions in papaya seedling up to 14 days after the inoculation. The essential oil derived from C. zeylanicum, applied as a preventive treatment, is efficient in controlling the size of lesions in papaya fruits, however, the effect is not observed if the essential oil is applied after infection.